Forsyth, 67, who calls himself Freddie, began an extraordinary love affair with German as a young boy. His father, a shopkeeper, never had the chance to learn languages, but was determined his son would. At nine, he was sent to France for consecutive summer holidays, staying with a French family. Then for three summers, aged 14 to 16, he stayed with German families in the British zone. By 15, he had passed his German and French A-levels.
"To send a 13-year-old son to go and live with a German family was considered very weird at the time. It was only 1951. The ruins and the rubble were still omnipresent. Our troops were everywhere. It was still an army of occupation."
To the locals, he was an object of curiosity. "They were wondering if I would have two heads. And of course the propaganda I'd been given - I was born in 1938 - led me to believe they might be very strange people indeed.
But they were exactly like me."
They called him Fritzi and marvelled at his ability to secure tins of Nescafe from the British base, while they were still drinking chicory. His hosts would think nothing of doing a day's work, then going down to the town hall to chip cement off rubble bricks to reconstruct the medieval rathouse (townhall) . "Everybody did voluntary work to rebuild Germany."
Forsyth returned to Germany in September 1963, just 11 months after the Cuban missile crisis, to take over the Reuters bureau in east Berlin. He recalls a terrifying period after the US President was shot dead by Lee Harvey Oswald, a communist and former defector to the Soviet Union. "I was inside east Berlin when Kennedy was assassinated. There was utter panic.
The Americans had B52 nuclear bombers based in Germany. People were stopping me in the street and asking if this meant war. They thought they were going to be nuked."
The only Westerner in the press corps, he donned shabby clothes to mix with East Germans away from their Russian masters. "When they learned I could pass for a German among Germans it scared the hell out of them."
He curried favour with the border guards by leaving oranges for them in the back of the car every time he passed through Checkpoint Charlie - you couldn't buy them in the east.
For the east Germans, he says, totalitarianism meant years of being watched and ordered about by party apparatchiks. Not sending your child to be indoctrinated at the Young Pioneers, for instance, could mean they didn't get to university, they didn't get a flat, or their parents could lose their jobs. "All sorts of things could happen if you didn't conform," says Forsyth.
Of the 17 million East Germans, there were 500,000 informers. When it all ended in 1991, the West Germans inherited warehouses of documents they are still going through 15 years later. Forysth says the Germans have been atoning for the war for decades . It is time for "ridiculous" British triumphalism to end.
"At 15 I found myself studying with the 18-year-olds doing all the classics, such as Schiller and Kleist. If you look at the German- speaking peoples in the 900 years since the crowning of Charlemagne, what a staggering contribution they have made to civilisation in every area: science, engineering, music, opera, painting, the great thinkers. Germans have contributed to the world every much as we Brits."
Frederick Forsyth's latest book, The Afghan (Bantam), will be published on October 5